This invention is concerned with improvements in push out devices for use with glassware forming machines.
In a conventional type of glassware forming machine known as an `I.S. machine`, several identical sections, usually eight to ten, but sometimes as many as 16, are mounted side by side and operate, cyclically but in off set timed relationship to make glass containers. Each section normally contains more than one mould for the making of such containers, usually two or three but increasingly commonly four: the machines are consequently described as double-, triple or quadruple- gob machines. In the operation of each section the requisite number of gobs of molten glass are provided to a set of parison moulds, in each of which a parison is formed, and the set of parisons is transferred to a set of blow moulds in which they are blown to the required shape. When the containers have been formed they are removed from the blow moulds by a take out mechanism, which picks up the containers and transfers them, usually to a dead plate on which they are cooled, and from which they are pushed out onto a conveyor by a push out device.
A typical push out device to remove moulded containers from a dead plate of a glassware forming machine a conveyor is shown in U.S. A 4771878 and comprises two pusher fingers which are mounted for a movement between an operative, extended, position and a retracted position by means of a pusher head, provided by a piston and cylinder device, and a rotary motor on which the pusher head is mounted and which is arranged to rotate the pusher head through approximately 90.degree. from an orientation in which it faces the dead plate to an orientation in which it faces the conveyor.
Conventional push out mechanism pushing the moulded articles onto a conveyor from the dead plate may, by appropriate spacing of the pusher fingers, alter the spacing of the moulded articles on the conveyor from that on the dead plate, but the amount by which this can be done is severely restricted by size and spacing of the containers and the need to position the fingers between the containers; the constraint is greater in a three or four gob machine than with a double gob machine. Also if an attempt is made to make a substantial change to the spacing one at least of the pusher fingers will necessarily be moving quite fast when it first contacts the appropriate container, thus risking damaging the container.
With increasing use of multi gob machines and efforts to increase the rate of operation of the glassware forming machines, conveyor speeds also have to increase; it is however desirable to have the conveyor speed as low as possible, partly for economy of operation, but also because with increasing conveyor speeds problems of instability of containers on the conveyor increase. For this reason it is often desirable to obtain a spacing of containers on the conveyor which is less that the spacing on the dead plate.
With certain machines, the widths of a section of the machine is in fact greater than the distance necessary to accommodate the containers removed from the section. In these cases it is sometimes desirable to ensure that the containers are placed on the conveyor with a spacing which is more than the spacing on the dead plate, to ensure that the containers on the conveyor are all equally spaced, thus to provide for uniformity of conditions of the containers on the conveyor and for ease of handing in subsequent operations.
It is one of the objects of the present invention to provide a push out device which enables the spacing of containers on the conveyor to be varied from the spacing of containers on the dead plate.